Frost control device



June 25, 1957 med Oct. 7 26, 1955 J. M. STINSON V 2 7%,699

FROST common DEVICE 2 Shets-Sheet 1 INVENTOR John Jiz'nson I ATTY6 June25,1957 J. M. STINSON 2,796,699

FROST CONTROL DEVICE Filed Oct. 26, 1955 2 Shee'ts-Sheet 2 :46 1/34 Hiill V 5 4 50 36a 37 35 I will: "L 9 11 INVENTOR John M J'Zz'naon UnitedStates PatentO ce,

This invention relates to orchard heaters, which at present are of twodistinct types, namely open-pot heaters and stack heaters.

Open-pot heaters do not burn their fuel economically and generate agreat amount of objectionable smoke.

However, they are small, very inexpensive, and large a and long andefficient service with a minimum of mainnumbers can be used to goodeffect, but'the objectionable 1 height before being dissipated thatenormous amounts of heat are needed to protect the crops, which are in azone below such height.

The fuel and labor expenses involved with such heaters under presentconditions therefore renders the use of the same so expensive orineffective that many orchardists have discontinued their use, deemingit a lesser evil to absorb the frost losses. The present invention isdirected to, and it is a major object to provide, a method and apparatusfor providing heat and distributing the same for frost prevention, whichwill be more effective, economical, and more readily adjustable tovarying conditions than is the case with the present structures. Suchstructure includes: (1) a burner assembly which generates heat ofsufiicient intensity, although with comparatively low heat output, toeconomically consume low grade petroleum fuels; (2) a means to convertthis intense heat into heat of very low intensity; (3) a means todistribute this low intensity heat over as wide and low level area as ispracticable to use with a portable apparatus; and (4) to incorporatedthe above features in a portable unitary structure which, together withany desired or necessary number of like structures, may be disposed inan orchard at strategically disposed points in relation thereto and toeach other, and where they may remain, ready for use, without attention,for a considerable time. p

The above mentioned apparatus, when in operation, functions toforcefully deliver heated air outwardly and downwardly toward the groundall about the device; the heated air having a substantial range, flowingfirst downwardly to impingethe ground, and then deflecting upwardly withcontinued outward flow; all whereby the device has a relatively largearea of effectiveness in the orchard wherein it is disposed.

An additional object of the invention is to provide a frost controldevice which embodies a novel burner assembly operative to produce arelatively high and constant heat adjustable in amount as desired; theburner assembly being adapted to use low cost petroleum fuel, such asdiesel oil or the like, and yet produce smokeless combustion, with amaximum of B. t. u. output from the fuel consumed.

A separate object of the invention'is to provide a frost control devicewhich includes a novel safety valve unit interposed in the fuel feedpipe leading to the burner assembly; such safety valve unit beingoperative-autotenance or repair being required.

7 Still another object of the invention is to provide a practical andreliable frost control device, and one which will be exceedinglyeffective for the purpose for which it is designed. 7

These objects are accomplished by means of such struc ture and relativearrangement of parts as will fully appear by a perusal of the following'specification and claims.

In the drawings:

Fig. '1 is an end elevation of the device.

Fig. 2 is an enlarged fragmentary sectional elevation of the devicetaken on line 22 of Fig.1.

Fig. 3 is an enlarged fragmentary side elevation showing the safetyvalve unit; the view being taken on line 33 of Fig. 1.

Fig. 4 is an enlarged fragmentary transverse sectional elevation takenon line 4-4 of Fig. 3.

Referring now more particularly to the drawings, and to the charactersof reference marked thereon, the improved frost control device ororchard heater comprises a stand, indicated generally at 1, which standis of open or skeleton construction. The stand 1 is comprised ofdownwardly divergent corner legs 2 connected together on all sides bytop tie bars 3, intermediate tie bars 4, and lower tie bars 5; all ofsaid bars being horizontal. The stand is of welded construction, thusavoiding the need of cross bracing, which would impede the free flow ofair from the deflector, later described. A vertical axis gasoline engine6 is supported from opposed ones of the intermedite tie bars 4 by crossmembers 7. The engine 6 includes 21 depending vertical drive shaft 8,and a relativelylarge-diameter, horizontally disposed air propeller 9 issecured to the shaft 8 by means of the propeller hub 16.

The propeller 9 runs within the confines of a horizontal im erforateguard ring 11 which is secured to and depends from'the cross members 7;the top of said guard ring 11 being fitted with a screen 12.

The engine 6 is protected from the elements by a shed roof 13 disposedthereabove and suitably secured in connection with the top of the stand1.

A relatively shallow, frusto-conical air deflector plate 14 is disposedadjacent but below the guard ring 11 in concentric relation thereto; theair deflector plate 14 being suspended from said guard ring 11 by aplurality of circumferentially spaced suspension bars '15. Thefrusto-conical air deflector plate 14 is of somewhat greater diameterthan the propeller 9 and guard ring 11, whereby to attain maximumdeflection of the air stream from said propeller. .1

A burnerasser'nbly; indicated generally at 16, is disposed below thedeflector plate 14 and comprises the following;

An' elongated, inverted, frusto-conical burner cone 17 is fixed at itsupper end in matching relation within the top opening of thefrusto-conical deflector plate 14, and thence depends therefrom toalower end termination adjacent but short of the horizontal plane'o'fthe lower tie bars 5. The burner cone 17 is open at the upper end 18 butclosed at the lower end 19, as shown; such cone in at least the lowerhalf thereof being provided with a multiplicity of perforations 20therethrough.

9 Within the burner cone 17, and adjacent but short of its lower end,said cone is fitted with an annular, upwardly inclined ring 21 which hasfluid-tight connection at its outer edge with said '--cone; the ring -21defining a central opening 22 therein, and also forming an an- :nularcatch trough 23 between said ring and the adjacent wall of the cone 17.Such adjacent wall has no perforations therein, whereby fuel fed intothe burner cone 17 from above said trough 23, in the manner here inafterdescribed, will be caught in such trough for vaporization if the fueldoes not fully vaporize before reaching such point. 7

A cylindrical open top burner pot 24 of greater diameter than the burnercone 17 is supported by cross members 25 which span between opposed onesof the lower tie bars said burner pot 24 extending upwardly in substantially spaced concentric relation about, at least the lower half ofthe burner cone 17. The upper edge of the burner pot 24 is preferablydisposed in a' horizontal plane approximately adjacent the correspondingplane of the lower edge of the air deflector plate 14; said burner pot24 having a multiplicity of perforations 26 therethrough.

The bottom 27 of the burner pot 24 has perforations 28 which precludethe undesirable accumulation of any unburned fuel which may drip intosaid burner pot.

A fuel tank 29 of drum type is suitably supported on top of the stand 1as by cradles 30; fuel from such tank delivering first through a needlevalve and strainer unit 31, and thence passing into a fuel feed pipe 32.The fuel feed pipe 32 extends downwardly and passes diagonally throughthe air deflector plate 14 and burner cone 17, terminating in adischarge end 33 disposed to deliver the fuel against the inner face ofsaid burner cone 17 clear of the perforations and at a point somedistance above the annular catch trough 23.

A safety valve unit, indicated generally at 34, is interposed in thefuel feed pipe 32 intermediate its ends; said safety valve unit beingoperative to permit of fuel flow in pipe 32 to the burner assembly 16only when the engine 6 is in operation. The construction and function ofthe safety valve unit 34 are, in detail, as follows:

The gas engine 6 includes an exhaust pipe 35 having a relatively shortextension 35:: which projects horizontally outwardly to a terminationlaterally out from the stand 1, and an upstanding valve block 36 isdisposed directly above said exhaust; the valve block 36 having a saddle37 on its lower end which engages and is, welded to said extension 35a.The valve block 36 may be removably supported-from the adjacent tie bar4 by a bracket 38.

Pipe extension 35a is removably secured to the main exhaust pipe 35 by aunion 35b, so that said extension,

together with the valve block, may be readily removed L for replacement,repairs, or servicing, if needed.

The valve block 36 is formed, from its upper end, with a vertical bore39, the lower portion of which forms a valve chamber 40. Intermediatethe ends of the valve chamber 40 it reduces in diameter and is thereshaped as an upwardly facing, tapered valve seat 41. A vertical plunger42 slidably engages in the bore 39, and said plunger is formed at itslower end with a taper valve 43 adapted for cooperative engagement withthe valve seat 41 when the plunger 42 is lowered.

The fuel feed pipe 32 is cut or divided intermediate its ends, with theadjacent end portions secured by couplings 44 and 45 in communicationwith the upper and lower ends, respectively, of the valve chamber 40.Thus, when the plunger 42 is lowered, with the taper valv'e 43 closedagainst the valve seat 41, fuel cannot feed in the pipe 32 below thesafety valve unit 34. V J

A post 46 is secured to, and upstands from, the valve block 36 inwardlyof the upwardly projecting portion of the plunger 42, and an arcuate arm47 is pivoted at its inner or rear end, as at 48, to the upper end ofthe post 46. The arcuate arm 47 extends in vertically swingable relationoutwardly from the pivot 48 in a downward direction; such arm passing inrelatively free-play relation through a bore 49 in the plunger 42.

At its outer end the arcuate arm 47 is fitted with a bafile areaeeeplate 50 which faces and lies in abutment with the outer end of theexhaust pipe 35 when the engine 6 is not in operation. The arcuate arm47 is then in a lowered position, as shown in dotted lines in Fig. 3,and at such time the plunger 42 is likewise lowered, with the tapervalve 43 closed against the seat 41. Consequently, when the engine 6 isnot in operation no fuel can flow in the feed pipe 32 below the safetyvalve unit 34.

However, when the engine 6 is in operation, with an exhaust blasteminating from the exhaust pipe 35, such blast forces the baflle plate50 outwardly, swinging the arcuate arm 47 upwardly to the full-lineposition of Fig. 3.. When this occurs the plunger 42 is shiftedupwardly, opening the taper valve 43 to a position above the seat 41 sothat fuel may flow through the safety valve unit 34; i. e., through thevalve chamber 40 and thence downwardly through the lower portion of thefeed pipe 32 into the burner assembly 16.

The cone, being closed at the bottom, provides a receptacle below thelowest row of perforations. 20 of a.

size to hold a small quantity of fuel, suificient for ready starting ofthe fire, which must be done before the motor is started, since theblast of air from the fan would extinguish any small flame.

After the fuel has been burning, with a continued inflow of fuel throughpipe 32, until a brisk fire is obtained, the motor is started to operatethe fan. The fire is then adjusted to provide the desired heat accordingto experience or reading of temperature and humidity instruments,suitably placed so that a temperature reading at the outermost range ofeffectiveness of the device, will be 1 or 2 above the criticaltemperature of the crops to be protected.

When the described frost control device is in use the engine 6 is inoperation, driving the propeller 9 at relatively high speed and creatinga forceful stream of air downwardlyout of the guard ring 11 which alsoforms an air deflector; the major portion of such air stream strikingthe deflector plate 14, but anotherportion of such air deliveringspirally downward into the burner cone 17.

The fuel, after passing the safety valve unit 34, de-

livers downwardly through the lower portion of the pipe 32 and feedsfrom the discharge end 33 directly into the burner cone 17. 7 The entireburner assembly 16 operates under relatively .high temperature, so thatthe fuel as it feeds from the discharge end 33 is, in the major portion,immediately vaporized within the burner cone 17. The ignited vaporizedfuel burns in part within the cone 17, and in part exteriorly thereof;this for the reason that the air stream, whirling spirally downward insaid cone, carries part of the combustible mixture through theperforations 20. Thus, there is a complete combustion of the fuel afterit is vaporized, either within the cone 17, between the latter and theburner pot 24, or outside the pot by reason of the fuel being forced outthrough perforations 26; all to the end that the burner assembly 16functions to produce a maximum of B. t. u.s with'a smokeless fire, ifproper control of the flow of fuel is exercised.

Any fuel which may not fully vaporize when discharged from the pipe 33,and when it strikes the inner face of the cone 17 drops into the trough23, where vaporization is completed; the trough being directly in themajor area of combustion.

The relatively high heat created by the burner assembly 16 rises againstthe under side of the air deflector plate 14,heating such plate andthence rolling downwardly and outwardly to discharge from the peripherythereof. The downward air blast or stream from the propeller 9, strikingthe top of the deflector plate 14, is warmed by heat exchange therefrom,and then delivers laterally in an outward and downward direction. As thewarmed air leaves the periphery of the deflector plate 14, it also picksup and carries with it the heat flow which is escaping laterallyoutwardly from beneath said deflector plate 14 at said periphery. Thus,the heat from the burner assembly 16 is employed in a most eflectivemanner to raise the temperature of the air stream, from the propeller 9,as deflected by the plate 14.

From the plate 14 the heated air is discharged with an initiallyrelatively high velocity, in a downward and outward direction over acontinuous circular path. This air stream passes through thesurroundingstatic air, its velocity gradually decreasing by reason of theresistance offered by such static air. The heated air stream finallyimpinges gently against the ground at a flat angle some distance fromthe stand 1, and rebounds and rises. The heated air, during its downwardand upward movement, imparts its heat to the surrounding air to raisethe temperature thereof to the desired extent, depending on the initialheat of the fire. 1

With the aforesaid directional control of the warmed air stream,together with the fact that such stream has considerable range, thedevice is effectivefor frost controlover a relatively wide area withinthe orchard wherein such device is disposed; the fire being regulatedso'that the air adjacent the limits of the range of the device will beheated only slightly above the temperature of the air outside thisrange.

Fuel feed to the burner assembly 16 is controlled, within accuratelimits, by manual adjustment of the needle valve and strainer unit 31over a wide range of heat output; the operator, by visual attention tothe flame within the burner assembly 16, being thus able to regulatefuel combustion so that good combustion and economy over said range isobtainable, with adequate heat output.

By reason of the inclusion of the safety valve unit 34, together withthe fact that the gasoline engine 6 and fuel supply in the tank 29 willrun for a number of hours, the device when started can thereafter beleft unattended for a considerable period of time. Upon the engine 6stopping for any reason, the safety valve unit 34 will function to shutoff the fuel supply to the burner assembly 6 so that damage, byoverheating, to the parts of the device cannot accidentally occur.

With a suitable number of the above described frost control devicesstrategically disposed, the prevention of frost damage to an entireorchard crop can be accomplished in an effective and practical manner;the devicesby reason of their portabilitybeing capable of being disposedat the most advantageous points within an orchard area.

From the foregoing description it will be readily seen that there hasbeen produced such a device as will substantially fulfill the objects ofthe invention, as set forth herein.

While this specification sets forth in detail the present and preferredconstruction of the device, still in practice such deviations from suchdetail may be resorted to as do not form a departure from the spirit ofthe invention, as set forth herein.

Having thus described the invention, the following is claimed as new anduseful, and upon which Letters Patent are desired.

1. A frost control device comprising, in connection with a stand, arelatively exposed deflector plate having a downwardly and outwardlyinclined top surface, a burner assembly below the deflector plate inheating relation thereto, a propeller journaled above the deflectorplate operative to direct a forceful air stream downwardly against saidplate, an internal combustion engine connected in driving relation tothe propeller, said engine having an exhaust pipe with an exposed end, afuel tank, a fuel feed conduit leading from the tank to the burnerassembly, a valve unit arranged to control fuel feed through theconduit, the valve unit including a part movable between one positionwith said valve unit closed and another position with the same open, amovable baffle haust pipe, and mechanism connecting the baflie and partoperative to translate movement of the bafl'le by said exhaust blastinto motion of said part to said other position, the baflie moving thepart to said one position when the engine is off and the exhaust blastceases.

2. A frost control device, as in claim 1, in which the valve unitincludes a valve body, a plunger slidable in the body, a portion of saidplunger projecting from the body and comprising said part, saidmechanism embodying a swing arm pivoted at one end in connection withthe body and connected intermediate the ends With said portion of theplunger in a manner to reciprocate the same be tween said positions uponto and fro swinging of the arm, and the baflle being mounted on theother end of the arm.

3. A frost control device comprising, in connection with a stand, arelatively exposed substantially horizontal deflector plate of generallyconical form whereby the upper surface of the deflector plate slopesoutwardly and downwardly, a burner assembly below the deflector plate inheating relation thereto, and a driven propeller journaled above thedeflector plate operative .to direct a forceful air stream downwardlyagainst said plate, the plate being formed with a central opening; theburner assembly including a depending tubular burner member secured atits upper end to the deflector plate in communication with said centralopening therein, said tubular burner member being perforate, and acylindrical burner pot into which said burner member depends.

4. A frost control device comprising, in connection with a stand, arelatively exposed substantially horizontal defiector plate of generallyconical form whereby the upper surface of the deflector plate slopsoutwardly and downwardly, :a burner assembly below the deflector platein heating relation thereto, a driven propeller journaled above thedeflector plate operative to direct a forceful air stream downwardlyagainst said plate, the deflector plate being formed with a centralopening; the burner assembly including a depending tubular burner membersecured at its upper end to the deflector plate in communication withsaid central opening therein, and an annular upwardly openingtrough-forming ring secured internally in the tubular memberintermediate its ends; there being a fuel feed pipe disposed todischarge in said member against the inner surface thereof and at apoint above the trough.

5. A frost control device comprising, in connection with a stand, arelatively exposed, horizontal deflector plate of frusto-conicalconfiguration whereby the upper surface of said deflector plate slopesoutwardly and downwardly, a vertical axis propeller journaled above butadjacent the deflector plate operative to direct a forceful air streamdownwardly against said plate, means to drive the propeller, a burnerassembly below but adjacent the deflector plate in heating relationthereto, and means to feed fuel to said burner assembly; thefrustoconical deflector plate being formed with a central opening ofsubstantial diameter, the burner assembly including a depending tubularmember fixed in connection with said deflector plate in communicationwith said opening; said depending tubular member being elongated and ofinverted frustoconical configuration, at least the lower portion of saidtubular member being perforate, and a cylindrical burner pot of greaterdiameter than the tubular member surrounding at least the lower portionthereof in spaced symmetrical relation; the fuel feed means being a pipedisposed to discharge at one end into the tubular member intermediatethe ends of the latter.

6. A frost control device comprising an upstanding frame of openconstruction, an engine mounted in the frame a substantial distanceabove its lowermost end, the engine having a depending vertical shaft, avertical axis propeller secured on the shaft, a horizontal guard ringsecured to the frame extending about the propeller, a frusto-conicaldeflector plate disposed in coaxial relation below the guard ring, saidplate having a central opening,

a 7 means-suspending the deflector plate from the guard ring,an'elongated inverted frusto-conical burner member secured to thedefiectorplate in communication with said ,centralopening and dependingtherefrom, and an open top burner pot secured to the frame below thedeflector plate in position with said member projecting into said potfrom above, both said member and pot having perforations therein. V

7. A frost control device comprising an upstanding frame of openconstruction, an engine mounted in the frame a substantial distanceabove its lowermost end, the engine having a depending vertical shaft, avertical axis propeller secured on the shaft, a horizontal guard ringsecured to the frame extending about the propeller, a frusto-conicaldeflector plate disposed in coaxial relation below the guard ring, saidplate having a central opening, means suspending the deflector platefrom the guard ring, an elongated inverted frusto-conical burner membersecured to the deflector plate in communicationwith said central openingand depending therefrom, an open top burner pot secured, to the framebelow the deflector plate in position with said member projecting intosaid spot from above, both said member and pot having perforationstherein, a fuel tank mounted on the frame above the engine, and a fuelfeed conduit leading from the tank to a discharge end Within saidmember.

References Cited in the file of this patent UNITED STATES PATENTS

